Chapter 6 Blog: An Introduction to Energy, Enzymes, and Metabolism (Pavan)


In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.

 

A.  Daily Blog

10/13/10

Today, we discussed energy and its basic principles. Energy is defined as the ability to do work. The two types of energy are potential and kinetic. Kinetic energy is the energy of motion, while potential energy is energy stored due to structure or location. We then moved onto the laws of thermodynamics, which we touched upon earlier. The first law states that energy cannot be created or destroyed, only transformed. The second law states that every transformation of energy increases entropy (disorder) in the universe. However, as Dr. Weber explained, humans must work against the laws of thermodynamics to exist. We went over the equation ΔG = ΔGproducts - ΔGreactants. This equation models the amount of free energy, or usable energy created from a reaction. In exergonic reactions the equation would be negative, as energy is released in the process. In endergonic reactions, the equation is positive, as energy is used.

 

10/15/10

We continued the discussion of energy, and moved onto enzymes. Enzymes are proteins that act as catalysts for chemical reactions. They function by lowering the activation energy, the energy required to start a reaction. This is accomplished by straining the substrate's shape or bringing them closer together. A substrate binds to an enzyme at its active site. When available active sites are occupied by substrates, the enzymatic activity reaches maximum velocity (Vmax), and is saturated. Km is the amount of substrate required to bind half the enzymes. Enzymes are inhibited either competitively or non-competitively. Competitive inhibitors bind directly to the enzyme's active site, preventing substrate binding. Non-competitive inhibitors bind to allosteric sites (sites other than the active site), changing the enzyme's conformation to prevent substrate binding.

 

B.  Useful Materials